Robustness of end-systolic reconstructions in coronary dual-source CT angiography for high heart rate patients.

Objectives: Reconstruction of cardiac computed tomography (CT) images is challenging when the heart rate is higher than 65 beats per minute (bpm). The optimal reconstruction time is often found to be at the end-systolic phase, but image quality remains uncertain. Using dual-source (DS) CT and 83-ms temporal resolution, we evaluated the robustness of the temporal window with low motion during the end systole.

Methods: We studied 41 DSCT in consecutive patients with a heart rate >65 bpm. Eleven systolic reconstructions were performed every 20 ms between 200 ms and 400 ms of the R-R interval. The end-systolic temporal window (ESTW) was defined as the interval between the first and last selected phases judged adequate for diagnosis.

Results: Heart rates varied from 67 to 150 bpm. ESTW was always to be found greater than 100 ms. The mean ESTW was 178 ms (SD: 57 ms), and varied independently of heart rate. All data sets achieved diagnostic quality during the end-systolic phase at a time point between 35 and 50% of the R-R interval.

Conclusion: Our data suggest that CT with a temporal window below 100 ms may provide acceptable systolic reconstructions at any heart rate, in a large proportion of patients.